Ki is the 128-bit Individual Subscriber Authentication Key utilized as a secret key shared between the Mobile Station and the Home Location Register of the subscriber’s home network.
RAND is 128-bit random challenge generated by the Home Location Register.
SRES is the 32-bit Signed Response generated by the Mobile Station and the Mobile Services Switching Center.
Kc is the 64-bit ciphering key used as a Session Key for encryption of the over-the-air channel. Kc is generated by the Mobile Station from the random challenge presented by the GSM network and the Ki from the SIM utilizing the A8 algorithm.